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fix(realtime): restart the downlink pump after it crashes - #3732
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qbc2016 merged 1 commit intoNov 12, 2026
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The downlink pump runs without any exception guard, so a provider stream error or a handler exception kills the task. _on_downlink_done detects the crash and clears _connected so the next input reconnects, but it leaves the finished task in self._downlink — and connect() only creates a new pump when that reference is None. Every reconnect after a crash therefore succeeds without pumping the new session's events: the agent goes deaf for the rest of its lifetime. Clear the dangling reference in the crash branch so the next connect() starts a fresh pump, and pin the recovery with a regression test that crashes the first session's event stream and asserts the second session is pumped.
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AgentScope Version
2.0.12dev (main @
782bd43)Description
RealtimeAgent's downlink pump (_pump_downlinkinsrc/agentscope/agent/_realtime/_agent.py) runs without any exception guard: if the model's event stream raises (a provider SDK stream error) or_on_model_eventthrows, the exception escapes thewhile Trueand the pump task dies._on_downlink_donedetects the crash and clears_connected/_connected_eventso that, per its docstring, the "next input reconnects" — but it leaves the finished task inself._downlink, andconnect()only creates a new pump when that reference isNone(the only place it is reset isclose()). Every reconnect after a crash therefore succeeds — audio is pushed, the session opens — while nobody pumps the new session's events: the agent goes deaf for the rest of its lifetime, which is exactly the "silently dead session" the callback's docstring says it surfaces instead (#3731).Changes — the crash branch of
_on_downlink_donenow also clears the dangling reference, so the nextconnect()starts a fresh pump:How to test
New case in the existing
RealtimeAgentTest(tests/realtime_agent_test.py), driven by the file'sScriptedModel/FakeTransportfixtures:test_crashed_downlink_pump_is_replaced_on_reconnect— aCrashingSessionModelwhose first session'sevents()raises, whose second session behaves: fails onmain(the reconnect succeeds but the summary is empty — no events are ever pumped from the new session, andagent._downlink.done()is still true), passes with this fix (the second session's reply is delivered and the live pump is back);test_provider_timeout_reconnects_on_next_audio,test_old_downlink_cannot_disconnect_new_session, etc.) are untouched and still pass.python -m pytest tests/realtime_agent_test.py # 44 passed.Fixes #3731
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